4102b53392
This is the meat of the series which prevents any dcache alias creation by always keeping the U and K mapping of a page congruent. If a mapping already exists, and other tries to access the page, prev one is flushed to physical page (wback+inv) Essentially flush_dcache_page()/copy_user_highpage() create K-mapping of a page, but try to defer flushing, unless U-mapping exist. When page is actually mapped to userspace, update_mmu_cache() flushes the K-mapping (in certain cases this can be optimised out) Additonally flush_cache_mm(), flush_cache_range(), flush_cache_page() handle the puring of stale userspace mappings on exit/munmap... flush_anon_page() handles the existing U-mapping for anon page before kernel reads it via the GUP path. Note that while not complete, this is enough to boot a simple dynamically linked Busybox based rootfs Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_ARC_PAGE_H
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#define __ASM_ARC_PAGE_H
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#include <uapi/asm/page.h>
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#ifndef __ASSEMBLY__
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#define get_user_page(vaddr) __get_free_page(GFP_KERNEL)
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#define free_user_page(page, addr) free_page(addr)
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#define clear_page(paddr) memset((paddr), 0, PAGE_SIZE)
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#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
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#ifndef CONFIG_ARC_CACHE_VIPT_ALIASING
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#define clear_user_page(addr, vaddr, pg) clear_page(addr)
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#define copy_user_page(vto, vfrom, vaddr, pg) copy_page(vto, vfrom)
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#else /* VIPT aliasing dcache */
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struct vm_area_struct;
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struct page;
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#define __HAVE_ARCH_COPY_USER_HIGHPAGE
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void copy_user_highpage(struct page *to, struct page *from,
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unsigned long u_vaddr, struct vm_area_struct *vma);
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void clear_user_page(void *to, unsigned long u_vaddr, struct page *page);
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#endif /* CONFIG_ARC_CACHE_VIPT_ALIASING */
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#undef STRICT_MM_TYPECHECKS
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#ifdef STRICT_MM_TYPECHECKS
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/*
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* These are used to make use of C type-checking..
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*/
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typedef struct {
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unsigned long pte;
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} pte_t;
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typedef struct {
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unsigned long pgd;
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} pgd_t;
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typedef struct {
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unsigned long pgprot;
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} pgprot_t;
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typedef unsigned long pgtable_t;
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#define pte_val(x) ((x).pte)
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#define pgd_val(x) ((x).pgd)
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#define pgprot_val(x) ((x).pgprot)
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#define __pte(x) ((pte_t) { (x) })
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#define __pgd(x) ((pgd_t) { (x) })
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#define __pgprot(x) ((pgprot_t) { (x) })
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#define pte_pgprot(x) __pgprot(pte_val(x))
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#else /* !STRICT_MM_TYPECHECKS */
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typedef unsigned long pte_t;
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typedef unsigned long pgd_t;
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typedef unsigned long pgprot_t;
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typedef unsigned long pgtable_t;
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#define pte_val(x) (x)
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#define pgd_val(x) (x)
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#define pgprot_val(x) (x)
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#define __pte(x) (x)
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#define __pgprot(x) (x)
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#define pte_pgprot(x) (x)
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#endif
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#define ARCH_PFN_OFFSET (CONFIG_LINUX_LINK_BASE >> PAGE_SHIFT)
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#define pfn_valid(pfn) (((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
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/*
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* __pa, __va, virt_to_page (ALERT: deprecated, don't use them)
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*
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* These macros have historically been misnamed
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* virt here means link-address/program-address as embedded in object code.
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* So if kernel img is linked at 0x8000_0000 onwards, 0x8010_0000 will be
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* 128th page, and virt_to_page( ) will return the struct page corresp to it.
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* mem_map[ ] is an array of struct page for each page frame in the system
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*
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* Independent of where linux is linked at, link-addr = physical address
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* So the old macro __pa = vaddr + PAGE_OFFSET - CONFIG_LINUX_LINK_BASE
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* would have been wrong in case kernel is not at 0x8zs
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*/
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#define __pa(vaddr) ((unsigned long)vaddr)
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#define __va(paddr) ((void *)((unsigned long)(paddr)))
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#define virt_to_page(kaddr) \
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(mem_map + ((__pa(kaddr) - CONFIG_LINUX_LINK_BASE) >> PAGE_SHIFT))
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#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
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/* Default Permissions for page, used in mmap.c */
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#ifdef CONFIG_ARC_STACK_NONEXEC
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#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE)
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#else
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#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#endif
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#define WANT_PAGE_VIRTUAL 1
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#include <asm-generic/memory_model.h> /* page_to_pfn, pfn_to_page */
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#include <asm-generic/getorder.h>
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#endif /* !__ASSEMBLY__ */
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#endif
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